Objectivity and careful scientific processes are key when collecting climate change evidence. Climate experts James Renwick and Drew Bingham explain why.
Depending on how you look at that information, you can tell different stories.
It is entirely possible to … to look at the same data and come to different conclusions, and that’s why the scientific process is so valuable. We form an idea around why we think these data might be a certain way – in science, we call that a hypothesis – and then we go out and test that. You might collect the same data, and two groups might have different hypotheses for why those data are the way they are. You test one idea and you test the other, and over time, evidence will accumulate.
If you look at the data objectively – the changes in temperatures, say, over 100 years or 50 years – you see things warming up. You see the number of frosts decreasing, you see changes in where plants like to grow, you see ice melting in the Southern Alps, the big glaciers are getting smaller. This all adds up to one particular story – that the climate’s changing and it’s getting warmer.
Yes, you can always find some place where maybe it isn’t getting warmer. If you look at the report, you will find locations in New Zealand where the number of frosts has increased. It’s actually got colder at night. At the same time, it’s got warmer during the day. There are always little differences, little subtleties around the overall story. When you look at the entirety of the information, all the locations around New Zealand and around the globe for that matter, you get a very obvious message.
Professor James Renwick, Victoria University of Wellington
Drew Bingham, Ministry for the Environment
Gregor Macara, NIWA
Light airplane research mission and aerials of Southern Alps and Brewster Glacier; Auckland water dam during drought; storm footage, NIWA
Timelapse of Fox Glacier retreat between January 2014 and January 2015, Brian Anderson, Victoria University of Wellington
This resource has been produced with the support of the Ministry for the Environment and Stats NZ. (c) Crown Copyright.